About 20 years ago, my uncle hit upon this idea. Arby's roast beef used to have this deal. They'd give you a sack of ten Arby's roast beef sandwiches for $10. My uncle would buy the sack and then stick them right away into the freezer. My father and I tried that idea. It has to be roast beef or roast beef and cheddar sandwiches. It would work with anything with lettuce, etc. in it. But the lettuce would get soggy when you defrosted it. Then, you carefully peel the aluminum foil wrapper off, and put them in the microwave. About 45 seconds per sandwich, if I recall correctly. It was economical since it was a special. And it could be a snack or small meal.
I ate there once in the 1960s, as well as a couple of times at a Taco Bell. In the 70s I ate once at Del Taco, once at a Jack in the box. Dreadful! The good chains back then were Marie Callenders and El Torito.
I actually liked Arbys when I could eat there. They're not where I live now...... But I don't think I'd be interested in buying a bunch of those, freezing them and then reheat to eat. That sounds like a whole lot of long term ass cancer going on.